Heart rate score, a measure related to chronotropic incompetence in pacemaker patients

High initial heart rate score is an independent predictor of new atrial high-rate episodes in pacemaker patients with sinus node dysfunction

BACKGROUND

Heart rate score (HRSc), the percentage of atrial depolarizations in the largest paced and sensed 10-beats/min histogram bin recorded in cardiac devices, is associated with several adverse outcomes, but it remains uncertain whether HRSc independently predicts atrial high-rate episodes (AHREs) in patients with sinus node dysfunction (SND) undergoing pacemaker (PM) implantation.

OBJECTIVE

This study aimed to determine whether initial HRSc after PM implantation predicts new-onset AHREs in patients with SND.

METHODS

Patients had Boston Scientific PMs implanted for SND from 2012 to 2021 at Cleveland Clinic, University of Occupational and Environmental Health, Japan, Kyushu Rosai Hospital, and JCHO Kyushu Hospital. Patients were excluded if they had atrial fibrillation before PM implantation or AHREs within 3 months after implantation. Subsequent AHREs after implantation were evaluated and correlated with HRSc.

RESULTS

During 48.9 (interquartile range, 25.7-50.4) months, 130 consecutive PM patients (76 ± 10 years; 40% male) had a median initial HRSc of 74% (57%-86%). AHREs defined by >1%, >6 h/d burden, and atrial tachycardia response events >24 hours developed in 27 of 130 (21%), 15 of 130 (12%), and 9 of 130 (7%), respectively. For each definition, patients with HRSc ≥80% had higher occurrence of AHREs than those with HRSc <80% (both P = .008, log-rank test). After adjustment for age, race, comorbidities, left ventricular ejection fraction, left atrial diameter, and cumulative percentage of right atrial and right ventricular pacing, initial HRSc ≥80% (hazard ratio, 3.33; 95% CI, 1.35-8.18; P = .009) and male sex (hazard ratio, 2.59; 95% CI, 1.06-6.33; P = .04) independently predicted AHREs.

CONCLUSION

HRSc ≥80% is associated with new-onset, device-determined AHREs for patients undergoing PM implantation for SND. HRSc may have prognostic and therapeutic implications.

Heart rate score in remote monitoring: An additional tool for predicting outcomes in heart failure with reduced ejection fraction

BACKGROUND

Heart rate score (HRS) ≥ 70% has been associated with arrhythmic events and mortality but these studies were not specific for heart failure (HF) patients. We hypothesized that HRS ≥ 70% obtained from remote monitoring (RM) is associated with HF hospitalizations and arrhythmic events in HF with reduced ejection fraction (HFrEF).

METHODS

HRS was calculated from RM in patients with HFrEF and ICD or CRT-D. Two groups were defined: HRS ≥ 70% (G1, n = 55) and HRS < 70% (G2, n = 48) RESULTS: A total of 103 patients were included (64.4 ± 13.04 years, 69.9% male, mean left ventricular ejection fraction (LVEF) 33.62 ± 11.97% and FUP 61.7 ± 38.87 months). The device was CRT-D in 59.2% and ICD in 40.8% and the majority (90.3%) had the device implanted in primary prevention. G1 patients were more frequently male (p = .017) and had more coronary disease (p = .035). HRS ≥70% was an independent predictor for unplanned HF hospitalizations (OR: 1.905 (95% CI: 1.328-3.649), p < .001)). The indication for device implantation (primary vs. secondary prevention), type of device, NYHA class, age, gender and LVEF were not independent predictors of the outcome. VF (4.9 ± 20.0 G1 vs. 1.1 ± 5.47 G2, p = .046) and VT episodes were more prevalent in G1 (3.1 ± 8.93 G1 vs. 0.3 ± 1.59 G2, p = .026), as well as appropriate device shocks (4.3 ± 12.06 G1 vs. 0.3 ± 1.49 G2, p = .023). There was no difference in inappropriate shocks or mortality outcomes between groups.

CONCLUSION

HRS ≥70% obtained from RM was an independent predictor of HF hospitalizations and was associated with arrhythmic events with VT and VF episodes and appropriate device shocks in HFrEF patients.

Initial heart rate score predicts new-onset atrial tachyarrhythmias in pacemaker patients

AIMS

Heart rate score (HRSc), the per cent of atrial paced and sensed event in the largest 10 b.p.m. rate histogram bin of a pacemaker, predicts survival in patients with cardiac devices. No correlation between HRSc and development of atrial fibrillation (AF) has been reported. In this study, we evaluated the relationship between pacemaker post-implantation HRSc and the incidence of newly developed atrial tachyarrhythmias (ATAs).

METHODS AND RESULTS

Patients with dual-chamber pacemakers, implanted 2013-17, with the LATITUDE remote monitoring data with ≥600 000 beats of histogram data collected at baseline were included (N = 34 543). Heart rate score was determined from the initial 3-month post-implantation histogram data. Patients were excluded if they had ATAs, defined as atrial high-rate episodes >5 min or >1% of right atrial beats >170 b.p.m. during the initial 3 months post-implantation. New ATAs, after the baseline period, were defined by each of the following: >1, >10, or >25% of atrial beats >170 b.p.m. or atrial tachycardia response (ATR) events >24 h. Patients were followed a median of 2.8 (1.0-4.0) years. The incidence of ATAs increased in proportion to HRSc (log-rank P-value <0.001), and the initial HRSc ≥70% was associated with increased ATAs by all definitions. Patients with initial HRSc ≥70% were older, had a higher percentage of right atrium pacing (%RA pacing), had a lower percentage of right ventricular pacing (%RV pacing), and were more likely programmed with rate-response vs. subjects with HRSc <70%. Initial HRSc (hazard ratio: 1.07, 95% confidence interval: 1.05-1.09; P < 0.0001) independently predicted ATAs after adjusting for age, gender, %RV pacing, and rate-response programming. The %RA pacing and initial HRSc were correlated.

CONCLUSION

Heart rate score independently predicts any subsequent duration of ATAs in pacemaker patients.

Lower rate limit for pacing by cardiac resynchronization defibrillators: Should lower rate programming be reconsidered?

BACKGROUND

No real-world large database associates lower rate limit (LRL) programming and survival of subjects with cardiac resynchronization therapy-defibrillators (CRT-Ds).

OBJECTIVE

The purpose of this study was to test the hypothesis that lower LRL programming is independently associated with survival, and that LRL and heart rate score (HrSc) are associated.

METHODS

All dual-chamber CRT-D devices in the Remote Patient Monitoring (RPM) ALTITUDE database (2006-2011) were queried. Baseline HrSc was defined as the percentage of all atrial sensed and paced beats in the tallest 10-beat histogram bin postimplant. LRL was assessed during repeated RPM uploads. Using a Cox model multivariable analysis, relationships between LRL, survival, HrSc, and other variables were evaluated. Survival was determined by query of death indices.

RESULTS

Data analyzed included 61,881 subjects (mean follow-up 2.9 years). LRL ranged from 40 to 85 bpm. Baseline lower LRL was associated with younger age, less atrial fibrillation, female sex, and lower HrSc (P <.001 for all covariates). Lower LRL was associated with improved survival, with LRL 40 associated with the largest survival benefit. This was significant for all 3 HrSc subgroups (P <.001). An interaction between HrSc and LRL was observed, with the largest survival difference between HrSc groups observed at LRL-40 (P <.001).

CONCLUSION

LRL programming and HrSc were associated, and lower values of both were associated with improved survival in a large database of CRT-D subjects. Relationships between survival, LRL programming, and HrSc merit further study.